Improv champs behind HBO series

I have long been a fan of the improv-heavy work of Christopher Guest, who as writer, director and actor has given us “Waiting for Guffman,” “A Mighty Wind,” “For Your Consideration,” “Best in Show” and other works.

The movies have storylines but they are at their best when the characters are set free to talk their way into ever more comical absurdity — while somehow remaining real and even touching.

Guest has relied on an informal repertory company including the likes of Michael McKean, Bob Balaban, Jane Lynch and Fred Willard.

Another regular player has been Jim Piddock, and he along with Guest created “Family Tree,” premiering at 10:30 p.m. Sunday on HBO.

“Family Tree” stars Chris O’Dowd — Kristen Wiig’s policeman beau in “Bridesmaids” and Thomas-John in “Girls” — as Tom Chadwick, a 30-year-old Brit who is adrift, jobless and recently dumped by his girlfriend.

When his great aunt dies, Tom inherits a chest full of memorabilia, most of it unrecognizable to him. He is especially taken by a photograph of an old-time military man who may have been his great-grandfather.

Tom begins researching, discovering new views of his family, and of the strange turns that lives take.

O’Dowd, new to Guest’s work but not to improv, is very good at seeming vulnerable and lost.

The story seemed to dry up as it went along. But Guest’s work has a way of sneaking into your head, settling down and becoming more likable the longer it stays. Maybe “Family Tree” just needs to settle in.